The Poverty of the Stimulus

From: Susie (
Date: Tue Apr 16 1996 - 17:26:36 BST


In order to communicate, the majority of human beings use spoken
language to do so. With the aid of `grammar', languages follow
specified rules, so that its speakers can share this means of
communication to their advantage. However, every different language
has a different kind of grammar. Grammatical devices are used in
different ways around the world. Although these rules of spoken
language are unsimilar, it is possible to say one meaning in all
languages. Infact, `anything you find in one language can also be
found in every other language, perhaps at a more abstract level of
representation', (Chomsky). Spoken language has its differences but
we cannot deny the similarities. All have phrase structure rules,
rules of linear order, tense and auxilaries. These properties may
not convey exactly the same significance or relevance in every
language but they no doubt occur somewhere.

Grammar is a different component in every language but Universal
Grammar (UG) is one for every. UG is the way the mind logically
thinks. `It specifies the allowable mental representations (stands
for) and operations that all languages are confined to use',
(Pinker). The thoughts everyone experiences are guided by the UG
facility. By consequence, language is a means of communicating it.
As Skinner said, ` thinking is a form of verbal behaviour. Verbal
behaviour is a prime manifestation of "thought"'. It is thought
that every child is born with UG; the ability to acquire (have)
language is species specific. Even without environmental cues,
`children learn languages governed by highly subtle and abstract
principles'(Chomsky). UG cannot be learned from environmental
examples; it seems to be a mental structure which is innate (born
with). If environmental exposure was its origin, there appears to
be very little or no evidence as to how a child knows wrong rules
from right ones.

This is where the issue of poverty of the stimulus arises. Before
this subject goes any further, what exactly is poverty of the
stimulus? Well, to say the least, by the age of four , children are
excellent speakers of language, using complex structures extremely
well. However, the big question is, how do they gather such an
ability with so few examples? They may receive an abundance of
positive things to say correctly but how do they know not to say
incorrect phrases? It's amazing how a child of four comes out with
new correct sentences never heard of before. Where does the
guidance come from? `Children have no manual to consult', (Pinker
and Bloom). A child never gets negative examples , only positive
ones, therfore these are too impoverished for him or her to learn UG
rules from. Instead,'children exploit special ways in which their
mothers talk to them by making unself conscious errors', (Pinker).
The point with poverty of the stimulus is that if UG was learn't
through environmental guidance, there just wouldn't be enough data
for the child to learn from. One would have thought more evidence
was needed. So, it seems the child already has UG to begin with ,
hence, mistakes are rarely made and has no need for corrections.

Even so, a child's exposure to positive evidence is by no way
lacking. Positive evidence is the information available to a child
about which groups of words are correct grammatical sentences of a
particular language. Basically, a four year old child only produces
or hears positive examples of UG from others such as parents or
other carers. It is strongly suggested that, 90% of the time,
children speak correctly, (Pinker). Infact, studies carryed out by
Pinker, Stromswold, Crain and Marcus et al, found that for every
rule that was observed, children of three obeyed them the majority
of the time. Acquisition of UG may be thought to be innate but it is
unable to strive alone. Only in cooperation with environmental cues
will it succeed. Most children have access to spoken language.
They need some form of linguistic input to acquire a language. If
grammatical abilities are of biological origin they are ` too
formalised and systematic to generate sound speech, words and
grammatical constructions on their own' (Pinker). Grammatical rules
are not all straight forward and compliant; they often stray from
their proper places. For one, there are exceptions to every rule.
In the case of language, there are no doubt more than one.
Deviations of these kind probably answer up to the environmental
exposure everyone faces. It must be said, rules, especially rules
of language (grammar) change with experience and practice.
Subsequently, language develops both with the innate UG device and
the environmental exposure of the language.

All these positive examples of the correct way to `speak' seem to be
ample evidence for a child to have the facility of UG. On the other
hand, `children do not need to hear a full language; as long as they
are in a community with other children and some source of individual
words, they will invent one on their own, often in a single
generation', (Pinker). Children of such a young age adapt extremely
easily to the environment they live in. Case studies by Bickerton
found examples of the above situation. There have been children
that grew up in plantations and slave colonies who were actually
exposed to crude pidgin (type of language several different native
speakers use) but infact grew up to speak genuinely new languages.
These are better known as expressive `creoles' with their own
complex grammar, (Bickerton, 1984, see also chapter by Newport and

Even though the sheer existence of UG puts the child's ability of
learning a language to a great advantage, he or she needs to hear an
existing language to learn it. Naturally sounding sentences in
colloquial speech (every day talk) are classed as `grammatical',
positive evidence. These may include such utterances as slang
(Pinker 1994a); for example, `where are you going'? and, `to the
shops'. Grammatical samples drive language acquisition. Even
supposedly ungrammatical examples are mean't to guide our language
formation, for instance, `he be coming soon'. Plus , many people
consider the grammar of working class folk to be poor, whereas, in
fact, it is scientifically complex in differing ways, depending on
the language.

Children do experience lots of positive evidence from their mother
tongue language. In many respects, this should make up for the
impoverished negative evidence. Maybe it is because there is so
much positive exposure to be guided by, there is no reason for
completely `wrong' utterances to occur; they have never been heard
in the first place. However, the child still knows what not to say
and what to say. This all miraculously happens without being
formally instucted but growing up in normal environmental conditions
hearing spoken utterances. The best part of these being produced by
the child's parents.

Coming from the other direction, negative evidence for UG is
somewhat under nourished; this is why the child's language
acquisition device is so impoverished by incorrect grammatical
utterances. There is plenty of stimuli for correct, well formed
grammatical sentences, but absolutely none, if any, for bad ones.
One would have expected to hear both aspects of a language in order
to learn which is the better one to produce. Funnily enough,
though, the child's brain never gets stimulation of such a negative
kind. In general terms, negative of UG consists of information
available to the child about sentences that are not proper. From a
young age, the majority of childrens' efforts to speak are not
corrected. How does this explain their practically perfect use of
language by the time they reach four years of age? It comes across
as a mystery as to how a child this age simply knows what can't be
said if external experience is the only cause for acquiring it.

In a paper written by Pinker, different hypotheses for negative
evidence were suggested. The way a child acquires a language
(English especially) could take four possible routes. For a start,
it should be acknowledged that childrens' language differs from
adults'. The first theory mentioned claims the child's hypothesis
language (H) (basis for reasoning of what the child thinks is an
appropriate language which can be understood) is separate in parts
from the language later to be acquired (to have), referred to as the
target language (T). A second theory hints that the child's
language and the (t) language actually intersect; the child
supposedly only uses some correct grammatical sentences. Thirdly,
another explanation says the the child's (H) language is infact a
subset or mini version of the target language (T), where the child
has succeeded to speak some good English. However, all these
explanations for acquiring a language surrendered to evidence
suggesting otherwise. It was more likely to be incorrect to develop
a language in the above ways just from hearing positive evidence of
UG without hearing wrong examples. A fourth theory described the
child's hypothesis (H) language as being a superset (used to its
full extent) of the target language (T); for instance, stems of
irregular verbs may be used in the past tense(we broke it, we went,
we breaked it, we goed). Similarly, this was discovered impossible.
 Negative evidence of UG would be needed in order to hear
corrections. In seldom an environmental situation, the fact that
negative evidence is non existent would proove impossible for a
child to produce a superset of the target language (T). The child
would guess too large a language which the world would never
correct. Obviously, there are limits as to how much a child can
possibly say because there would be things no one could understand.

In attempts to research behind the reasoning of UG acquisition,
experiments have been carryed out on young children. MacWhinney and
Snow (1985,1990,1991) experimented with young children, where they
were asked to answer sentences and describe pictures. The aim of
these practicals was to get the children to indicate what sounded
`silly' to them. In this light, an apparent existence of UG could
be conveyed. It was also discovered that, within the first year of
life, children can control speech muscles and are sensitive to
phonetic (vocal differences in meanings of words) distinctions used
in their parents language. Indeed, this ability is produced before
the comprehension of words so learning doesn't necessarily rely on
sound and meaning of a language.

In general terms, childrens' language development takes the same
path world wide. By the first year, their first words are similar.
Basic necessities of life are appreciated as very important and this
shows in their initial use of the language; for example, utterances
concerning food, clothing and people are heard. Another study found
that young children rapidly adapt this basic language into a more
complicated one. Childrens' two or three word utterances resembled
examples of longer sentences expressing a complete and more
complicated idea. Three children were studied; even though they
didn't ever produce a sentence as complex as `mum gave John lunch in
the kitchen', they did mutter strings containing all these
components aswell as in the correct order (Brown 1973, Bloom 1970,
Pinker 1984). Once again, this ability comes with the
experience of positive UG use but no negative use.

Be that as it may, there still has to be some source of negative
evidence. A language cannot survive without it. Gold and Pinker
claim that if the child has no negative evidence and works out a
rule that generates a superset of a language, he or she will have no
way of knowing that he or she is wrong, (Gold 1967, Pinker 1979,
1989). The environmental constraints don't allow the child access
to negative evidence of UG so there must be an underlying biological
answer. There has to exist, a mechanism that either avoids
generating too large a language or that can survive for generations.
 Skinner's behaviourist's claim that language learning depends on
parents' reinforcement of childrens' grammatical errors was tested
by Roger Brown and Camille Hanlon (1970). Adults responses to
grammatically well formed and ill formed phrases were divided into
approvals (eg: `Yes good') and those of unapprovals (eg: `No that's
not right'). Results illustrated that there was no correlation
between reinforcement and language learning. Parents didn't
differentially express approval or disapproval to their child's
utterances. Instead, approval depended on whether the child's
statement was true. Infact, parents don't understand their
children's well formed sentences any better than their badly formed

The reason why negative evidence does'nt answer the UG acquisition
problem is because the amount of sentences a child is exposed to is
finite (limited). Utterances of sentences are heard not the whole
sentence, which can be deffective in many ways, for example slurred
speech, slips of the tongue and mispronounciations. Plus, children
don't have explicit guidance from a speech community seeing as they
make few errors. Adults tend not to follow systematic correction
because in reality, they are happy the child is speaking. Anyway,
childrens' language intake is limited by their short attention span
and their restricted short term capacity. These cognitive
limitations have to affect complex utterances heard. The only
reliable source of linguistic data has to be simple sentence
utterances for the child. So, all in all, the information that is
available to guide the process of UG acquisition is severely
impoverished; it cannot be driven by the environmental existence of
data, (Norbert Heinstein).

Therefore it must be assumed that the child uses simple well formed
sentences excluding `negative evidence' (information that a sentence
is ill formed) to acquire UG. Children must come with a rich innate
structure that guides language acquisition and grammar construction,
otherwise how do they have such knowledge as not to say one thing
but another? Children come biologically equiped to vocalise,
produce and recognise particular classes of speech sounds (Mehler,
1981, C.J Darwin, 1987). It is thought that the `capacity to
acquire a language is species specific and genetically transmitted
which depends on that acquired by maturation and socialisation'
(Chomsky). This biological view has strong reasoning for being
maintained. Environmental aid may support the innate structure of
UG acquisition but nature is the number one factor. In conclusion,
the `poverty of the stimulus' purely exists due to environment's
unresolved constraints.


Natural language and natural selection (Steven Pinker and Paul

 Learnability, Hyperlearning and Poverty of the stimulus
(Geoffery K Pullum)

 Language Acquisition (Steven Pinker). An
Invitation to cognitive science, 2nd edition,volume
1-language.Cambridge, MA:MIT Press.

Natural language and UG -essays in linguistic
theory, volume 1, edited by John Lyons, Cambridge Press.

As time goes by- Tense and UG (Norbert Heinstein).

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